Debt collectors for banks, mobile phone companies and even a language teaching institute are increasingly using violence and arson to get their clients' money back, police said yesterday. Investigators say the use of criminal intimidation and criminal damage has spread from its traditional use by loanshark gangs to mainstream companies. The number of criminal damage cases linked to debt collection in Chai Wan, Shau Kei Wan and North Point soared by more than 50 per cent to 173 in the first nine months of this year from 113 in the same period last year, said Chief Inspector Chu Hon-keung, Shau Kei Wan assistant divisional commander. The figures reveal that the number of criminal intimidation cases reported in Eastern District increased from 45 between January and September last year to 54 in the same period this year. Mr Chu said the economic downturn was to blame. 'Due to economic problems, people who have lost their jobs are unable to settle their debts,' he said. Debt-collection firms appointed by banks, finance companies and other firms are promised at least 40 per cent of the debt they collect. If debtors fail to pay, unscrupulous collectors use a combination of nuisance calls, chaining up doors, jamming door locks and daubing threatening slogans in red paint on walls. Mr Chu said the use of violence or arson attacks could be found in serious cases. 'In the past, people owing money from loanshark syndicates could end up with such problems,' he said. 'Nowadays, people will meet the same problems even if they fail to pay mobile telephone bills, housing loans or credit-card debt.' Senior Inspector Lawrence See Kwong-tak from Eastern District's anti-triad section said a debtor received a phone call threatening his family if he failed to settle an outstanding mobile phone bill of $100. Another victim bought a set of language teaching aids worth more than $10,000 from a language institute and settled the bills by monthly payments. However, he lost his job and was unable to pay the outstanding sum of about $8,000. He then received threatening phone calls saying he would be assaulted if he did not pay. Mr See said most cases connected to illegal debt collection involved outstanding credit-card payments or gambling debts. But the force says proving that debt-collection firms are involved in illegal activity is a problem because victims are afraid.